Gregory Chen, M.D.
NPI 1699853457 · Urology Physician · Hayward, CA
Enrolled with Medicare as Practitioner - Urology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Gregory Chen, M.D. is a Urology Physician provider in Hayward, CA (NPI 1699853457).
Provider details
- NPI number
- 1699853457
- Entity type
- Individual
- Primary specialty
- Urology PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- No
- License
- G84622 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
19 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 20 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Tamsulosin Hcl | 530 | 260 |
| Finasteride | 426 | 172 |
| Trospium Chloride | 195 | 91 |
| Terazosin Hcl | 162 | 65 |
| Cefadroxil | 90 | 66 |
| Mirabegronbrand: Myrbetriq | 69 | 32 |
| Ciprofloxacin Hcl | 49 | 45 |
| Methenamine Hippurate |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-11-01
- Last updated
- 2021-12-13
Frequently asked questions
- What is Gregory Chen's NPI number?
- Gregory Chen's National Provider Identifier (NPI) is 1699853457, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Gregory Chen's specialty?
- Gregory Chen is listed in the NPPES registry with a primary specialty of Urology Physician (Allopathic & Osteopathic Physicians).
- Where is Gregory Chen located?
- Gregory Chen's practice location on file with NPPES is 27303 Sleepy Hollow Ave S, Hayward, CA 94545-4203.
- What is Gregory Chen's phone number?
- The practice phone number listed in the NPPES registry for Gregory Chen is (510) 454-1000.
- Does Gregory Chen accept Medicare?
- Gregory Chen is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Gregory Chen's NPI active?
- Yes — Gregory Chen's NPI (1699853457) is active in the NPPES registry as of the last update on 2021-12-13.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.